ffmpeg/libavcodec/h264_refs.c

790 lines
27 KiB
C

/*
* H.26L/H.264/AVC/JVT/14496-10/... reference picture handling
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* H.264 / AVC / MPEG-4 part10 reference picture handling.
* @author Michael Niedermayer <michaelni@gmx.at>
*/
#include <inttypes.h>
#include "internal.h"
#include "avcodec.h"
#include "h264.h"
#include "h264dec.h"
#include "golomb.h"
#include "mpegutils.h"
#include <assert.h>
static void pic_as_field(H264Ref *pic, const int parity)
{
int i;
for (i = 0; i < FF_ARRAY_ELEMS(pic->data); ++i) {
if (parity == PICT_BOTTOM_FIELD)
pic->data[i] += pic->linesize[i];
pic->reference = parity;
pic->linesize[i] *= 2;
}
pic->poc = pic->parent->field_poc[parity == PICT_BOTTOM_FIELD];
}
static void ref_from_h264pic(H264Ref *dst, H264Picture *src)
{
memcpy(dst->data, src->f->data, sizeof(dst->data));
memcpy(dst->linesize, src->f->linesize, sizeof(dst->linesize));
dst->reference = src->reference;
dst->poc = src->poc;
dst->pic_id = src->pic_id;
dst->parent = src;
}
static int split_field_copy(H264Ref *dest, H264Picture *src, int parity, int id_add)
{
int match = !!(src->reference & parity);
if (match) {
ref_from_h264pic(dest, src);
if (parity != PICT_FRAME) {
pic_as_field(dest, parity);
dest->pic_id *= 2;
dest->pic_id += id_add;
}
}
return match;
}
static int build_def_list(H264Ref *def, int def_len,
H264Picture * const *in, int len, int is_long, int sel)
{
int i[2] = { 0 };
int index = 0;
while ((i[0] < len || i[1] < len) && index < def_len) {
while (i[0] < len && !(in[i[0]] && (in[i[0]]->reference & sel)))
i[0]++;
while (i[1] < len && !(in[i[1]] && (in[i[1]]->reference & (sel ^ 3))))
i[1]++;
if (i[0] < len && index < def_len) {
in[i[0]]->pic_id = is_long ? i[0] : in[i[0]]->frame_num;
split_field_copy(&def[index++], in[i[0]++], sel, 1);
}
if (i[1] < len && index < def_len) {
in[i[1]]->pic_id = is_long ? i[1] : in[i[1]]->frame_num;
split_field_copy(&def[index++], in[i[1]++], sel ^ 3, 0);
}
}
return index;
}
static int add_sorted(H264Picture **sorted, H264Picture * const *src,
int len, int limit, int dir)
{
int i, best_poc;
int out_i = 0;
for (;;) {
best_poc = dir ? INT_MIN : INT_MAX;
for (i = 0; i < len; i++) {
const int poc = src[i]->poc;
if (((poc > limit) ^ dir) && ((poc < best_poc) ^ dir)) {
best_poc = poc;
sorted[out_i] = src[i];
}
}
if (best_poc == (dir ? INT_MIN : INT_MAX))
break;
limit = sorted[out_i++]->poc - dir;
}
return out_i;
}
static void h264_initialise_ref_list(const H264Context *h, H264SliceContext *sl)
{
int i, len;
if (sl->slice_type_nos == AV_PICTURE_TYPE_B) {
H264Picture *sorted[32];
int cur_poc, list;
int lens[2];
if (FIELD_PICTURE(h))
cur_poc = h->cur_pic_ptr->field_poc[h->picture_structure == PICT_BOTTOM_FIELD];
else
cur_poc = h->cur_pic_ptr->poc;
for (list = 0; list < 2; list++) {
len = add_sorted(sorted, h->short_ref, h->short_ref_count, cur_poc, 1 ^ list);
len += add_sorted(sorted + len, h->short_ref, h->short_ref_count, cur_poc, 0 ^ list);
assert(len <= 32);
len = build_def_list(sl->ref_list[list], FF_ARRAY_ELEMS(sl->ref_list[0]),
sorted, len, 0, h->picture_structure);
len += build_def_list(sl->ref_list[list] + len,
FF_ARRAY_ELEMS(sl->ref_list[0]) - len,
h->long_ref, 16, 1, h->picture_structure);
if (len < sl->ref_count[list])
memset(&sl->ref_list[list][len], 0, sizeof(H264Ref) * (sl->ref_count[list] - len));
lens[list] = len;
}
if (lens[0] == lens[1] && lens[1] > 1) {
for (i = 0; i < lens[0] &&
sl->ref_list[0][i].parent->f->buf[0]->buffer ==
sl->ref_list[1][i].parent->f->buf[0]->buffer; i++);
if (i == lens[0]) {
FFSWAP(H264Ref, sl->ref_list[1][0], sl->ref_list[1][1]);
}
}
} else {
len = build_def_list(sl->ref_list[0], FF_ARRAY_ELEMS(sl->ref_list[0]),
h->short_ref, h->short_ref_count, 0, h->picture_structure);
len += build_def_list(sl->ref_list[0] + len,
FF_ARRAY_ELEMS(sl->ref_list[0]) - len,
h-> long_ref, 16, 1, h->picture_structure);
if (len < sl->ref_count[0])
memset(&sl->ref_list[0][len], 0, sizeof(H264Ref) * (sl->ref_count[0] - len));
}
}
/**
* print short term list
*/
static void print_short_term(const H264Context *h)
{
uint32_t i;
if (h->avctx->debug & FF_DEBUG_MMCO) {
av_log(h->avctx, AV_LOG_DEBUG, "short term list:\n");
for (i = 0; i < h->short_ref_count; i++) {
H264Picture *pic = h->short_ref[i];
av_log(h->avctx, AV_LOG_DEBUG, "%"PRIu32" fn:%d poc:%d %p\n",
i, pic->frame_num, pic->poc, pic->f->data[0]);
}
}
}
/**
* print long term list
*/
static void print_long_term(const H264Context *h)
{
uint32_t i;
if (h->avctx->debug & FF_DEBUG_MMCO) {
av_log(h->avctx, AV_LOG_DEBUG, "long term list:\n");
for (i = 0; i < 16; i++) {
H264Picture *pic = h->long_ref[i];
if (pic) {
av_log(h->avctx, AV_LOG_DEBUG, "%"PRIu32" fn:%d poc:%d %p\n",
i, pic->frame_num, pic->poc, pic->f->data[0]);
}
}
}
}
/**
* Extract structure information about the picture described by pic_num in
* the current decoding context (frame or field). Note that pic_num is
* picture number without wrapping (so, 0<=pic_num<max_pic_num).
* @param pic_num picture number for which to extract structure information
* @param structure one of PICT_XXX describing structure of picture
* with pic_num
* @return frame number (short term) or long term index of picture
* described by pic_num
*/
static int pic_num_extract(const H264Context *h, int pic_num, int *structure)
{
*structure = h->picture_structure;
if (FIELD_PICTURE(h)) {
if (!(pic_num & 1))
/* opposite field */
*structure ^= PICT_FRAME;
pic_num >>= 1;
}
return pic_num;
}
static void h264_fill_mbaff_ref_list(H264SliceContext *sl)
{
int list, i, j;
for (list = 0; list < sl->list_count; list++) {
for (i = 0; i < sl->ref_count[list]; i++) {
H264Ref *frame = &sl->ref_list[list][i];
H264Ref *field = &sl->ref_list[list][16 + 2 * i];
field[0] = *frame;
for (j = 0; j < 3; j++)
field[0].linesize[j] <<= 1;
field[0].reference = PICT_TOP_FIELD;
field[0].poc = field[0].parent->field_poc[0];
field[1] = field[0];
for (j = 0; j < 3; j++)
field[1].data[j] += frame->parent->f->linesize[j];
field[1].reference = PICT_BOTTOM_FIELD;
field[1].poc = field[1].parent->field_poc[1];
}
}
}
int ff_h264_build_ref_list(const H264Context *h, H264SliceContext *sl)
{
int list, index, pic_structure;
print_short_term(h);
print_long_term(h);
h264_initialise_ref_list(h, sl);
for (list = 0; list < sl->list_count; list++) {
int pred = sl->curr_pic_num;
for (index = 0; index < sl->nb_ref_modifications[list]; index++) {
unsigned int modification_of_pic_nums_idc = sl->ref_modifications[list][index].op;
unsigned int val = sl->ref_modifications[list][index].val;
unsigned int pic_id;
int i;
H264Picture *ref = NULL;
switch (modification_of_pic_nums_idc) {
case 0:
case 1: {
const unsigned int abs_diff_pic_num = val + 1;
int frame_num;
if (abs_diff_pic_num > sl->max_pic_num) {
av_log(h->avctx, AV_LOG_ERROR,
"abs_diff_pic_num overflow\n");
return AVERROR_INVALIDDATA;
}
if (modification_of_pic_nums_idc == 0)
pred -= abs_diff_pic_num;
else
pred += abs_diff_pic_num;
pred &= sl->max_pic_num - 1;
frame_num = pic_num_extract(h, pred, &pic_structure);
for (i = h->short_ref_count - 1; i >= 0; i--) {
ref = h->short_ref[i];
assert(ref->reference);
assert(!ref->long_ref);
if (ref->frame_num == frame_num &&
(ref->reference & pic_structure))
break;
}
if (i >= 0)
ref->pic_id = pred;
break;
}
case 2: {
int long_idx;
pic_id = val; // long_term_pic_idx
long_idx = pic_num_extract(h, pic_id, &pic_structure);
if (long_idx > 31) {
av_log(h->avctx, AV_LOG_ERROR,
"long_term_pic_idx overflow\n");
return AVERROR_INVALIDDATA;
}
ref = h->long_ref[long_idx];
assert(!(ref && !ref->reference));
if (ref && (ref->reference & pic_structure)) {
ref->pic_id = pic_id;
assert(ref->long_ref);
i = 0;
} else {
i = -1;
}
break;
}
}
if (i < 0) {
av_log(h->avctx, AV_LOG_ERROR,
"reference picture missing during reorder\n");
memset(&sl->ref_list[list][index], 0, sizeof(sl->ref_list[0][0])); // FIXME
} else {
for (i = index; i + 1 < sl->ref_count[list]; i++) {
if (sl->ref_list[list][i].parent &&
ref->long_ref == sl->ref_list[list][i].parent->long_ref &&
ref->pic_id == sl->ref_list[list][i].pic_id)
break;
}
for (; i > index; i--) {
sl->ref_list[list][i] = sl->ref_list[list][i - 1];
}
ref_from_h264pic(&sl->ref_list[list][index], ref);
if (FIELD_PICTURE(h)) {
pic_as_field(&sl->ref_list[list][index], pic_structure);
}
}
}
}
for (list = 0; list < sl->list_count; list++) {
for (index = 0; index < sl->ref_count[list]; index++) {
if (!sl->ref_list[list][index].parent) {
av_log(h->avctx, AV_LOG_ERROR, "Missing reference picture\n");
if (index == 0 || h->avctx->err_recognition & AV_EF_EXPLODE)
return AVERROR_INVALIDDATA;
else
sl->ref_list[list][index] = sl->ref_list[list][index - 1];
}
}
}
if (FRAME_MBAFF(h))
h264_fill_mbaff_ref_list(sl);
return 0;
}
int ff_h264_decode_ref_pic_list_reordering(H264SliceContext *sl, void *logctx)
{
int list, index;
sl->nb_ref_modifications[0] = 0;
sl->nb_ref_modifications[1] = 0;
for (list = 0; list < sl->list_count; list++) {
if (!get_bits1(&sl->gb)) // ref_pic_list_modification_flag_l[01]
continue;
for (index = 0; ; index++) {
unsigned int op = get_ue_golomb_31(&sl->gb);
if (op == 3)
break;
if (index >= sl->ref_count[list]) {
av_log(logctx, AV_LOG_ERROR, "reference count overflow\n");
return AVERROR_INVALIDDATA;
} else if (op > 2) {
av_log(logctx, AV_LOG_ERROR,
"illegal modification_of_pic_nums_idc %u\n",
op);
return AVERROR_INVALIDDATA;
}
sl->ref_modifications[list][index].val = get_ue_golomb(&sl->gb);
sl->ref_modifications[list][index].op = op;
sl->nb_ref_modifications[list]++;
}
}
return 0;
}
/**
* Mark a picture as no longer needed for reference. The refmask
* argument allows unreferencing of individual fields or the whole frame.
* If the picture becomes entirely unreferenced, but is being held for
* display purposes, it is marked as such.
* @param refmask mask of fields to unreference; the mask is bitwise
* anded with the reference marking of pic
* @return non-zero if pic becomes entirely unreferenced (except possibly
* for display purposes) zero if one of the fields remains in
* reference
*/
static inline int unreference_pic(H264Context *h, H264Picture *pic, int refmask)
{
int i;
if (pic->reference &= refmask) {
return 0;
} else {
for(i = 0; h->delayed_pic[i]; i++)
if(pic == h->delayed_pic[i]){
pic->reference = DELAYED_PIC_REF;
break;
}
return 1;
}
}
/**
* Find a H264Picture in the short term reference list by frame number.
* @param frame_num frame number to search for
* @param idx the index into h->short_ref where returned picture is found
* undefined if no picture found.
* @return pointer to the found picture, or NULL if no pic with the provided
* frame number is found
*/
static H264Picture *find_short(H264Context *h, int frame_num, int *idx)
{
int i;
for (i = 0; i < h->short_ref_count; i++) {
H264Picture *pic = h->short_ref[i];
if (h->avctx->debug & FF_DEBUG_MMCO)
av_log(h->avctx, AV_LOG_DEBUG, "%d %d %p\n", i, pic->frame_num, pic);
if (pic->frame_num == frame_num) {
*idx = i;
return pic;
}
}
return NULL;
}
/**
* Remove a picture from the short term reference list by its index in
* that list. This does no checking on the provided index; it is assumed
* to be valid. Other list entries are shifted down.
* @param i index into h->short_ref of picture to remove.
*/
static void remove_short_at_index(H264Context *h, int i)
{
assert(i >= 0 && i < h->short_ref_count);
h->short_ref[i] = NULL;
if (--h->short_ref_count)
memmove(&h->short_ref[i], &h->short_ref[i + 1],
(h->short_ref_count - i) * sizeof(H264Picture*));
}
/**
* @return the removed picture or NULL if an error occurs
*/
static H264Picture *remove_short(H264Context *h, int frame_num, int ref_mask)
{
H264Picture *pic;
int i;
if (h->avctx->debug & FF_DEBUG_MMCO)
av_log(h->avctx, AV_LOG_DEBUG, "remove short %d count %d\n", frame_num, h->short_ref_count);
pic = find_short(h, frame_num, &i);
if (pic) {
if (unreference_pic(h, pic, ref_mask))
remove_short_at_index(h, i);
}
return pic;
}
/**
* Remove a picture from the long term reference list by its index in
* that list.
* @return the removed picture or NULL if an error occurs
*/
static H264Picture *remove_long(H264Context *h, int i, int ref_mask)
{
H264Picture *pic;
pic = h->long_ref[i];
if (pic) {
if (unreference_pic(h, pic, ref_mask)) {
assert(h->long_ref[i]->long_ref == 1);
h->long_ref[i]->long_ref = 0;
h->long_ref[i] = NULL;
h->long_ref_count--;
}
}
return pic;
}
void ff_h264_remove_all_refs(H264Context *h)
{
int i;
for (i = 0; i < 16; i++) {
remove_long(h, i, 0);
}
assert(h->long_ref_count == 0);
for (i = 0; i < h->short_ref_count; i++) {
unreference_pic(h, h->short_ref[i], 0);
h->short_ref[i] = NULL;
}
h->short_ref_count = 0;
}
static void generate_sliding_window_mmcos(H264Context *h)
{
MMCO *mmco = h->mmco;
int nb_mmco = 0;
assert(h->long_ref_count + h->short_ref_count <= h->ps.sps->ref_frame_count);
if (h->short_ref_count &&
h->long_ref_count + h->short_ref_count == h->ps.sps->ref_frame_count &&
!(FIELD_PICTURE(h) && !h->first_field && h->cur_pic_ptr->reference)) {
mmco[0].opcode = MMCO_SHORT2UNUSED;
mmco[0].short_pic_num = h->short_ref[h->short_ref_count - 1]->frame_num;
nb_mmco = 1;
if (FIELD_PICTURE(h)) {
mmco[0].short_pic_num *= 2;
mmco[1].opcode = MMCO_SHORT2UNUSED;
mmco[1].short_pic_num = mmco[0].short_pic_num + 1;
nb_mmco = 2;
}
}
h->nb_mmco = nb_mmco;
}
int ff_h264_execute_ref_pic_marking(H264Context *h)
{
MMCO *mmco = h->mmco;
int mmco_count;
int i, av_uninit(j);
int current_ref_assigned = 0, err = 0;
H264Picture *av_uninit(pic);
if (!h->explicit_ref_marking)
generate_sliding_window_mmcos(h);
mmco_count = h->nb_mmco;
if ((h->avctx->debug & FF_DEBUG_MMCO) && mmco_count == 0)
av_log(h->avctx, AV_LOG_DEBUG, "no mmco here\n");
for (i = 0; i < mmco_count; i++) {
int av_uninit(structure), av_uninit(frame_num);
if (h->avctx->debug & FF_DEBUG_MMCO)
av_log(h->avctx, AV_LOG_DEBUG, "mmco:%d %d %d\n", h->mmco[i].opcode,
h->mmco[i].short_pic_num, h->mmco[i].long_arg);
if (mmco[i].opcode == MMCO_SHORT2UNUSED ||
mmco[i].opcode == MMCO_SHORT2LONG) {
frame_num = pic_num_extract(h, mmco[i].short_pic_num, &structure);
pic = find_short(h, frame_num, &j);
if (!pic) {
if (mmco[i].opcode != MMCO_SHORT2LONG ||
!h->long_ref[mmco[i].long_arg] ||
h->long_ref[mmco[i].long_arg]->frame_num != frame_num) {
av_log(h->avctx, AV_LOG_ERROR, "mmco: unref short failure\n");
err = AVERROR_INVALIDDATA;
}
continue;
}
}
switch (mmco[i].opcode) {
case MMCO_SHORT2UNUSED:
if (h->avctx->debug & FF_DEBUG_MMCO)
av_log(h->avctx, AV_LOG_DEBUG, "mmco: unref short %d count %d\n",
h->mmco[i].short_pic_num, h->short_ref_count);
remove_short(h, frame_num, structure ^ PICT_FRAME);
break;
case MMCO_SHORT2LONG:
if (h->long_ref[mmco[i].long_arg] != pic)
remove_long(h, mmco[i].long_arg, 0);
remove_short_at_index(h, j);
h->long_ref[ mmco[i].long_arg ] = pic;
if (h->long_ref[mmco[i].long_arg]) {
h->long_ref[mmco[i].long_arg]->long_ref = 1;
h->long_ref_count++;
}
break;
case MMCO_LONG2UNUSED:
j = pic_num_extract(h, mmco[i].long_arg, &structure);
pic = h->long_ref[j];
if (pic) {
remove_long(h, j, structure ^ PICT_FRAME);
} else if (h->avctx->debug & FF_DEBUG_MMCO)
av_log(h->avctx, AV_LOG_DEBUG, "mmco: unref long failure\n");
break;
case MMCO_LONG:
// Comment below left from previous code as it is an interesting note.
/* First field in pair is in short term list or
* at a different long term index.
* This is not allowed; see 7.4.3.3, notes 2 and 3.
* Report the problem and keep the pair where it is,
* and mark this field valid.
*/
if (h->short_ref[0] == h->cur_pic_ptr)
remove_short_at_index(h, 0);
/* make sure the current picture is not already assigned as a long ref */
if (h->cur_pic_ptr->long_ref) {
for (j = 0; j < FF_ARRAY_ELEMS(h->long_ref); j++) {
if (h->long_ref[j] == h->cur_pic_ptr)
remove_long(h, j, 0);
}
}
if (h->long_ref[mmco[i].long_arg] != h->cur_pic_ptr) {
remove_long(h, mmco[i].long_arg, 0);
h->long_ref[mmco[i].long_arg] = h->cur_pic_ptr;
h->long_ref[mmco[i].long_arg]->long_ref = 1;
h->long_ref_count++;
}
h->cur_pic_ptr->reference |= h->picture_structure;
current_ref_assigned = 1;
break;
case MMCO_SET_MAX_LONG:
assert(mmco[i].long_arg <= 16);
// just remove the long term which index is greater than new max
for (j = mmco[i].long_arg; j < 16; j++) {
remove_long(h, j, 0);
}
break;
case MMCO_RESET:
while (h->short_ref_count) {
remove_short(h, h->short_ref[0]->frame_num, 0);
}
for (j = 0; j < 16; j++) {
remove_long(h, j, 0);
}
h->poc.frame_num = h->cur_pic_ptr->frame_num = 0;
h->mmco_reset = 1;
h->cur_pic_ptr->mmco_reset = 1;
break;
default: assert(0);
}
}
if (!current_ref_assigned) {
/* Second field of complementary field pair; the first field of
* which is already referenced. If short referenced, it
* should be first entry in short_ref. If not, it must exist
* in long_ref; trying to put it on the short list here is an
* error in the encoded bit stream (ref: 7.4.3.3, NOTE 2 and 3).
*/
if (h->short_ref_count && h->short_ref[0] == h->cur_pic_ptr) {
/* Just mark the second field valid */
h->cur_pic_ptr->reference = PICT_FRAME;
} else if (h->cur_pic_ptr->long_ref) {
av_log(h->avctx, AV_LOG_ERROR, "illegal short term reference "
"assignment for second field "
"in complementary field pair "
"(first field is long term)\n");
err = AVERROR_INVALIDDATA;
} else {
pic = remove_short(h, h->cur_pic_ptr->frame_num, 0);
if (pic) {
av_log(h->avctx, AV_LOG_ERROR, "illegal short term buffer state detected\n");
err = AVERROR_INVALIDDATA;
}
if (h->short_ref_count)
memmove(&h->short_ref[1], &h->short_ref[0],
h->short_ref_count * sizeof(H264Picture*));
h->short_ref[0] = h->cur_pic_ptr;
h->short_ref_count++;
h->cur_pic_ptr->reference |= h->picture_structure;
}
}
if (h->long_ref_count + h->short_ref_count -
(h->short_ref[0] == h->cur_pic_ptr) > h->ps.sps->ref_frame_count) {
/* We have too many reference frames, probably due to corrupted
* stream. Need to discard one frame. Prevents overrun of the
* short_ref and long_ref buffers.
*/
av_log(h->avctx, AV_LOG_ERROR,
"number of reference frames (%d+%d) exceeds max (%d; probably "
"corrupt input), discarding one\n",
h->long_ref_count, h->short_ref_count, h->ps.sps->ref_frame_count);
err = AVERROR_INVALIDDATA;
if (h->long_ref_count && !h->short_ref_count) {
for (i = 0; i < 16; ++i)
if (h->long_ref[i])
break;
assert(i < 16);
remove_long(h, i, 0);
} else {
pic = h->short_ref[h->short_ref_count - 1];
remove_short(h, pic->frame_num, 0);
}
}
print_short_term(h);
print_long_term(h);
return (h->avctx->err_recognition & AV_EF_EXPLODE) ? err : 0;
}
int ff_h264_decode_ref_pic_marking(H264SliceContext *sl, GetBitContext *gb,
const H2645NAL *nal, void *logctx)
{
int i;
MMCO *mmco = sl->mmco;
int nb_mmco = 0;
if (nal->type == H264_NAL_IDR_SLICE) { // FIXME fields
skip_bits1(gb); // broken_link
if (get_bits1(gb)) {
mmco[0].opcode = MMCO_LONG;
mmco[0].long_arg = 0;
nb_mmco = 1;
}
sl->explicit_ref_marking = 1;
} else {
sl->explicit_ref_marking = get_bits1(gb);
if (sl->explicit_ref_marking) {
for (i = 0; i < MAX_MMCO_COUNT; i++) {
MMCOOpcode opcode = get_ue_golomb_31(gb);
mmco[i].opcode = opcode;
if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG) {
mmco[i].short_pic_num =
(sl->curr_pic_num - get_ue_golomb(gb) - 1) &
(sl->max_pic_num - 1);
}
if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG) {
unsigned int long_arg = get_ue_golomb_31(gb);
if (long_arg >= 32 ||
(long_arg >= 16 && !(opcode == MMCO_SET_MAX_LONG &&
long_arg == 16) &&
!(opcode == MMCO_LONG2UNUSED && FIELD_PICTURE(sl)))) {
av_log(logctx, AV_LOG_ERROR,
"illegal long ref in memory management control "
"operation %d\n", opcode);
return -1;
}
mmco[i].long_arg = long_arg;
}
if (opcode > (unsigned) MMCO_LONG) {
av_log(logctx, AV_LOG_ERROR,
"illegal memory management control operation %d\n",
opcode);
return -1;
}
if (opcode == MMCO_END)
break;
}
nb_mmco = i;
}
}
sl->nb_mmco = nb_mmco;
return 0;
}